Effects of survey mode, patient mix, and nonresponse on CAHPS hospital survey scores.

OBJECTIVE: To evaluate the need for survey mode adjustments to hospital care evaluations by discharged inpatients and develop the appropriate adjustments.

DATA SOURCE: A total of 7,555 respondents from a 2006 national random sample of 45 hospitals who completed the CAHPS Hospital (HCAHPS [Hospital Consumer Assessments of Healthcare Providers and Systems]) Survey.

STUDY DESIGN/DATA COLLECTION/EXTRACTION METHODS: We estimated mode effects in linear models that predicted each HCAHPS outcome from hospital-fixed effects and patient-mix adjustors.

PRINCIPAL FINDINGS: Patients randomized to the telephone and active interactive voice response (IVR) modes provided more positive evaluations than patients randomized to mail and mixed (mail with telephone follow-up) modes, with some effects equivalent to more than 30 percentile points in hospital rankings. Mode effects are consistent across hospitals and are generally larger than total patient-mix effects. Patient-mix adjustment accounts for any nonresponse bias that could have been addressed through weighting.

CONCLUSIONS: Valid comparisons of hospital performance require that reported hospital scores be adjusted for survey mode and patient mix.